The first thing you should do is
edit your post to not reveal who was driving, in line with the guidance in this thread:
READ THIS FIRST - Private Parking Charges Forum guide. If you're no longer able to edit the post, DM me with the edited version and I will change it for you.
I have removed the attachment of your PCN as you have left your reg number and PCN reference number visible - you should hide these and then re-upload it.
We also need to see some pictures of the signage at the site.
is any chance mention that [the driver] was actually in car?
Earlier in the post you say the driver left the car? If they weren't in the car, then you must not lie and say they were. At any rate, a car can still be deemed as parked if the driver is sat in it.